Consider the following list of particles:
Which one of the following options correctly describes the particles that are present in an aqueous solution of sodium chloride?
A. 1 and 2 only
B. 1, 2 and 3
C. 3 only
D. 1 only
E. 2 only
In this aqueous solution of NaCl (this means that we have salt and water since NaCl is in an aq. solution), we have molecules (H_2O molecules) and we have ions (Na^+ and Cl^-), but we do not have single atoms. Ions are charged atoms, but there is a difference between them.
Why does salt dissolve in water?
Water and salt are both polar, ‘like dissolves like’. Taking this deeper, we are dealing with charged molecules, the positive Na^+ ions will be attracted to the partially negative regions on the water molecules (towards the oxygen). Similarly, the negatively charged Cl^- ions will be attacked towards the partially positive hydrogen poles of the water molecules. The covalent bonds within the water are stronger than the ionic bonds within salt, and there is a pulling apart of the Na and Cl from each other from the strong attraction of the water molecules. The resulting solution is homogenous, a single-phase liquid.